Basically, at idle you can probably get 80 amps out of your alternator. You can charge a flat battery to 80 percent full in about 2 hours, so long as you alternator can manage produce around 14 volts at the battery terminals this whole time. Depending on what the battery is demanding.
In respect to this, what causes the alternator to fail?
One of the most common failures is bearing failure. The needle bearings that allow the rotor to spin freely inside the stator can break down from dirt and heat. When the bearings fail, the rotor will not spin efficiently and can eventually seize. Usually an alternator with bearings failure makes a loud grinding noise.
"Starting the engine draws 100 to 130 amps, and idling the car for 15 minutes might put back three or four amps," Brown-Harrison says. "If you're idling only for 15 to 20 minutes, the battery never truly gets recharged. So each time you start and leave it to idle, the charge will get lower and lower and lower."
However, letting your car idle is actually detrimental to the modern automotive engine, wastes gasoline, and causes environmental damage. In addition, engineers now estimate that it is more fuel efficient to turn a car off and on then to leave it running as long as the car will be off for more than 10 seconds.
So it will take more than 30 minutes to 1 hr to reach fully charged condition from a typical worst case of 70% state of charge of battery. But in a high way drive cycle with high rpm ranges the alternator will generate high amperes and battery will be more than 95% with in 30 minutes.
Defective alternator diode. A car alternator recharges the battery and powers certain electrical systems. If your alternator has a bad diode, your battery can drain. The bad diode can cause the circuit to charge even when the engine is shut off, and you end up in the morning with a car that won't start.
Problem: Lights flare excessively as engine speed increases. Solution: This is usually caused by an overcharged battery, which is typically the result of high alternator voltage. This can be caused by a short or ground in the rotor field winding within the alternator or a defective regulator.
A trickle charger usually operates at around 2 amps and it is going to take a long time to charge up your 12 volt car battery (read our full guide here). It can take as long as 24 hours to get the battery up to an acceptable charge, depending on how depleted your battery is when you start charging.
The battery is charged by an alternator on modern cars, or by a dynamo on earlier ones. Both are types of generator , and are driven by a belt from the engine. The alternator consists of a stator - a stationary set of wire coil windings, inside which a rotor revolves.
Determining Charge Time. The more discharged that your battery is, the longer it will take to recharge it. Batteries usually take several hours to recharge; if the battery is severely discharged (12.2 volts or less for an flooded battery) then it may take up to 12 hours or more to recharge.
Part 3 Preventing Problems
- Warm the engine with a block heater.
- Keeping your car's battery warm.
- Park indoors.
- Use thinner oil.
- Use gas line antifreeze with fuel stabilizer.
- For diesel engines, consider using fuel conditioner.
- Keep your fuel tank full.
If the battery voltage is below 11.85 and your charger is putting out a 5-amp charge rate, it will take about 12 hours to fully charge a battery with 400 to 500 cold cranking amps. The same battery will take about 6 hours to fully charge if the charge rate is 10 amps.
While a few variables may be involved with overcharging a car battery, the results are simple to check. A battery can quite simply die from being overcharged. This is the safest side-effect, but not the only thing that can happen. An overcharged battery will boil the sulfuric acid and distilled water mix.
A basic charger usually charges at around 2 amps - and so needs 24 hours to deliver the 48 amps needed to fully charge a flat, 48 amp hour battery. But there is a wide range of chargers with different charge rates on the market - from 2 to 10 amps. The higher the charge output, the faster a flat battery is recharged.
Once you are familiar with the basics of your battery charger, you can now connect it to the vehicle's battery. You can charge the battery while it is still inside the car or if it has been removed, either method is fine. First attach the positive (red) clamp to the positive post on the battery.
Make 2-3 back to back appointments, and ask the genius to replace the battery within that time. That should give 30 or 45 minutes to do the battery replacement. And it should really only take about 10-20 min including the paperwork.
Under these conditions, you can probably expect your car battery life to be about six years. On average, a car battery lasts between two and five years. If you live in the northern United States, your car battery lifespan will be longer, because you're in a cold climate.
Today most car batteries are sealed, and come more or less fully charged. Moreover, the charging circuits in modern cars are much better at avoiding excessive charging voltage. So unless you have an old car (at least forty years old) you have no need at all to worry about charging a new battery.
Memory effect, as it's called, affects NiMH batteries but it doesn't apply to your phone. In fact, you're phone's battery hates when you do that. Similarly, lithium-ion batteries don't need to be "calibrated" with a full charge and a full discharge when they're new.